Spectral and Luminescence Properties of Mixed-Ligand Eu3+ and Tb3+ Complexes with tris(3-[2′-pyridyl]-pyrazolyl)borate and Carboxylates Containing an N-Salicylideneimine Fragment

It has been shown by single crystal X-ray diffraction analysis that the salicylideneimine fragment of Tp^PyLn(sch)₂(H₂O) (Ln = Eu, Tb; Tp^Py– = tris(3-[2′-pyridyl]pyrazolyl)borate; schH = p-schH, m-schH are carboxylate Schiff bases prepared by the reaction of 4- and 3-aminobenzoic acids, respectively, with salicylaldehyde) is not coordinated to the metal ion. The obtained Tb³⁺ complexes exhibit ligand-centered emission, while in the luminescence spectra of Eu³⁺ compounds narrow bands of characteristic emission of Eu³⁺ are also observed. It is found that when the complexes are irradiated with UV light, the transformations of carboxylate ligands in the coordination compounds occur.